Abstract: By using 1990's radiation data,the work studied the solar total radiation characteristic of the middle part of South China Sea. The atmlsheric clear-fir transmissivity is about 0.75; for the late 1990's,3-year average of cloudage contributes about 28% of the possible maxinmum radiation energy;the annual mean total radiation is about 6763.7MJ/m²·a; the monthly mean radiation total for March～August stays around 650 MJ/m² · m,with August-December a dessending stage and January～March an ascending one.